CN1578186A - Power control method for remotely deployed communication service - Google Patents

Abstract

The present invention relates to a power control method for a transceiver unit for communicating data on discrete tones. The present invention is especially suitable for the communication service of remote deployment, and compared with the existing method, the performance is obviously improved. The proposed method comprises the steps of: determining for each individual tone a transmit power on the physical channel such that the transmit power maximizes a weighting function of the data rates attainable by the tone on the physical channel and on modeled adjacent channels, It is constrained that the transmit power complies with the transmit power limit, accumulating the data rate over the entire set of tones, adjusting the weights so that the total data rate on the modeled adjacent channels reaches some target data rate, and thus maximizing on the physical channel The total data rate of , with the constraint that each weight is the same over the entire set of tones.

Description

Power Control Method for Remotely Deployed Communication Services

technical field

The invention relates to a method for determining at least one operating transmission power on a physical channel for each of at least one tone.

Background technique

Such methods are known in the art, for example, Wei YU, Georges GINIS and John M. CIOFI published in June 2002 on the IEEE Journal of Selected Areas in Communications (J-SAC) titled "Distributed Multi -user PowerControl for Digital Subscriber Lines" article.

Spectrum management and power control are central issues in designing interference-limited multi-user digital communication systems such as Digital Subscriber Line (DSL) systems.

Due to the increasing demand for higher data rates, spectrum management and power control emerged as core issues for two reasons: First, high-rate DSL systems are moving to higher frequency bands, where crosstalk issues are more pronounced . Second, deploying DSL remotely may create strong crosstalk in adjacent lines.

Figure 1 illustrates the latter problem. The three transceiver unit pairs RT1/CP1, CO1/CP2 and CO2/CP3 are connected via twisted pair L1, L2 and L3, respectively. The twisted pairs L1, L2 and L3 are bundled together in a bundler B located on the way to the central office CO. Since they are close together, the lines generate electromagnetic interference with each other. Near-end crosstalk (NEXT) refers to the crosstalk caused by a transmitter located on the same side as a receiver. Far-end crosstalk (FEXT) refers to the crosstalk caused by a transmitter located on the other side. NEXT is usually much stronger than FEXT. To avoid NEXT, DSL uses frequency division multiplexing. Among them, the upstream (from the customer's building) and the downstream (to the customer's building) signals are assigned different frequency bands.

In order to shorten the loop length for the purpose of increasing the data rate, the transceiver unit RT1 is deployed closer to the customer premises CP1 eg via optical fiber OF. This is known as remote or RT deployed DSL as opposed to centrally or CO deployed DSL.

When the signal from the transceiver unit CO1 starts to couple with the line L1 in the bundler B, this signal is attenuated to a certain extent, thus producing a weak FEXT F12. On the contrary, when the signal from the transceiver unit RT1 starts to couple with the line L2, the signal from the transceiver unit RT1 is much stronger, thus producing a stronger FEXT F21.

Several power control methods have been proposed in the literature.

The cited document discloses a power control method in which each transceiver unit allocates power by waterfilling background noise and interference from other transceiver units. The power allocation of one transceiver unit affects the interference perceived by other transceiver units. This in turn affects their power allocation so that there is a coupling between the power allocations of different users. Rewatering uses an iterative process whereby each transceiver unit is refilled until a convergence point is reached.

The disclosed power control method is an implementation of dynamic spectrum management. It is adapted to coordinate the direct and crosstalk channels perceived by the transceiver units in each particular deployment. The result is a much less conservative design and thus higher performance.

The disclosed power control methods also result in the possibility that the transmit power spectral density (PSD) may exceed the spectral limits defined in the DSL standard. Therefore, the spectrum compatibility rules are not satisfied under method A. Instead, it relies on the testing of method B to guarantee compatibility. These tests are very complex. Furthermore, it is unclear whether spectral compatibility of rewatering under Method B can be guaranteed for all deployment scenarios.

Another deficiency of the disclosed power control method is that it basically performs a flat power backoff (PBO) on short loops, such as seen in RT deployed DSL. In this case, it inherits all the problems with flat PBOs.

Contents of the invention

It is an object of the present invention to alleviate these deficiencies.

According to the invention, this object is achieved in that said method comprises the following steps:

- determine the transmission power on the physical channel for each single tone in the at least one tone, so that the transmission power makes the data rate available on the physical channel and on the single tone and the weighting function of at least one parallel data rate obtainable on each channel of at least one model adjacent channel and on said single tone is maximized, constrained by the fact that said transmit power complies with a transmit power limit,

- determining therefrom the total data rate available on said physical channel and on said at least one tone, and the at least available on each of said at least one model adjacent channel and on said at least one tone A total parallel data rate,

- adjusting each weight of said weighting function such that said at least one total parallel data rate is higher than or equal to respective ones of at least one target data rate and so that said total data rate is maximized, constrained by, each weight of said weighting function is the same over said at least one tone,

The at least one operating transmit power is thus determined iteratively.

In general, power allocation problems are non-convex. This leads to numerically intractable problems that cannot be solved or cannot be solved with reasonable processing power.

However, the following simplifications yield approximately optimal PBO solutions:

- Each of said at least one tone is considered individually in the optimization process.

- The transmitted signal must comply with the transmit power limit.

- each weight of said weighting function is the same over said at least one tone.

Because the solution is within the spectrum constraints, there are no spectrum compatibility issues.

This technique lends itself to autonomous execution by defining protected services (worst case - sacrificed services), typically DSL deployed by COs. And as seen in DSL deployed by RT, the power allocation is still based on the channel. As a result, the solution is not overly conservative.

Changing the desired rate for the protected traffic allows different compromises between the range of DSL deployed by the CO and the data rate of the DSL deployed by the RT. This tradeoff can be changed to suit each geographic region. Therefore, operators can offer the most favorable traffic volumes based on the demographics of customers in an area.

This technique has been applied in RT-deployed Asymmetric DSL (ADSL) and RT-deployed Very High Speed Asymmetric DSL (VDSL) when legacy ADSL systems must be protected. This technique achieves significant throughput compared to traditional static spectrum management, where RT-deployed VDSL is prohibited from transmitting in the ADSL frequency band.

This technique is also applicable to upstream VDSL transmitters, where the signal from the far-end transmitter must be protected from the large crosstalk produced by the near-end transmitter.

The result is a simple, autonomous PBO approach for DSL especially suitable for CO and RT deployments.

The invention also relates to a transceiver unit comprising:

- a transmitter unit adapted to transmit at least one tone on a physical channel;

- A power control unit coupled to said transmitter unit and adapted to determine at least one operating transmit power on said physical channel for each of said at least one tone.

A similar purpose can be achieved by implementing the present power control method in said power control unit.

The invention also relates to a digital communication system comprising:

- at least one transceiver unit,

- a communication adaptation module coupled to said at least one transceiver unit via a data communication network,

Each transceiver unit of said at least one transceiver unit comprises:

- a transmitter unit adapted to transmit at least one tone on a physical channel,

Described communication adaptation module comprises:

- A power control unit adapted to determine at least one operating transmit power on said physical channel for each of said at least one tone.

A similar purpose can be achieved by implementing the power control method in the power control unit.

In this embodiment, the transceiver unit is freed from transmit power calculations and a savings in processing resources is obtained, but at the expense of network resources required to centralize the necessary information from the local entity, and autonomy of its operation .

Described data communication network represents any type of network that is suitable for transmitting data between its arbitrary ports, can be Local Area Network (LAN), such as Ethernet bus; Wide Area Network (WAN), such as ATM broadband network or Internet etc., and Regardless of the underlying communication technology used, the underlying communication technology may be circuit switching or packet switching communication, wired or wireless communication, and the like.

The scope of the present invention is not limited to DSL communication systems. The present invention is applicable to any type of digital communication system that transmits data on discrete tones, be it through discrete multi-tone (DMT) modulation, single carrier modulation, code division multiple access (CDMA) modulation, etc., and to any type of physical The transmission medium, which could be coaxial cable, fiber optics, atmosphere, vacuum, etc., where crosstalk is a possible noise source, but not necessarily a dominant one.

Another characteristic embodiment of the invention is that said determination of transmit power is restricted to a discrete set of predetermined data rates performed by the coding and/or modulation scheme employed on said physical channel.

This simplification allows finding low-complexity solutions.

Another characteristic embodiment of the invention is that said weighting function is a weighted sum.

Other mathematical functions with weighting are conceivable with the data rate and the at least one parallel data rate as input, possibly with another optimization purpose.

Other characteristic embodiments of the invention are described in the appended claims.

It should be noted that the term "comprising", also used in the claims, should not be interpreted as being limited to the means listed thereafter. Therefore, the scope of the expression "an apparatus comprising means A and B" shall not be limited to an apparatus consisting of components A and B only, and it means that for the present invention, the relevant components of the apparatus are A and B.

Similarly, it should be noted that the term "coupled", also used in the claims, should not be construed as being limited to a mere direct connection. Thus the scope of the expression "a device A coupled to a device B" should not be limited to devices or systems in which the output of device A is directly connected to the input of device B. It means that there is a path between the output of A and the input of B, which may be a path that includes other devices or devices.

Description of drawings

The above and other objects and features of the present invention can be more clearly understood by referring to the following description of an embodiment in conjunction with the accompanying drawings, and the present invention itself can be best understood, wherein:

- Figure 1 shows the problem that a remote deployment of DSL may cause strong crosstalk in adjacent lines.

- Figure 2 represents the interfering channel model,

- Figure 3 represents a DSL transceiver unit according to the invention,

- Figure 4 represents the rate regions of the different PBO methods including proposed schemes.

- Figure 5 represents a DSL communication system according to the invention.

Detailed ways

Consider the interfering channel model given in Figure 2. There are N adjacent channels C ₁ to C _N connecting each _of the N transmitters X ₁ to X N to each of the N receivers Y ₁ to Y _N .

Let H _nn denote the direct channel transfer function from transmitter X _N to receiver Y _N . Denote the crosstalk channel transfer function from transmitter X _m to receiver Y _n by H _nm (m≠n).

In addition to interference, each receiver suffers from zero-mean additive white Gaussian noise (AWGN), whose PSD is denoted σ _n ² .

Let _Sn denote the PSD of each transmitted signal.

The achievable data rate R _n on channel C _n is given by Shannon's formula (when all interference is considered as noise):

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&Integral;</span>}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; max</span>}}}{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; n</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; nm</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; df</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

where Γ denotes the SNR-gap. The SNR-gap Γ defines the gap between the actual coding and modulation scheme and the channel capability. The SNR-gap Γ depends on the coding and modulation scheme used and also on the target probability of error. According to the theoretical capability, Γ=0dB.

In one embodiment of the invention, the signal is sampled at a sampling frequency F _{s which} is at least twice the bandwidth of the signal. The signal is captured over a time window _Tc that matches a DMT symbol, ie the frequency interval 1/ _Tc matches the tone interval.

The achievable data rate R _n is then given by:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; K</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; n</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">k</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; nm</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

in:

- denote by {f ₁ ,...,f _K } the set of tones on which the current optimization process is performed, f ₁ to f _K being harmonics of the fundamental frequency 1/ _Tc ,

- S _{n, k} = S _n (f _k ),

- H _{nm, k} = H _nm (f _k ),

${<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">k</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; .</span>$

In one embodiment of the invention, {f ₁ , . . . , f _K } are defined by the applicable DSL standard.

In another embodiment, {f ₁ , . . . , f _K } is a subset thereof.

Let B _n,k denote the number of bits that a particular tone f _k can carry on channel C _n .

We get:

in is rounded down to the nearest value in the set {b ₀ =0, b ₁ , . . . , b _L }. The set {b ₀ , b ₁ , . . . , b _L } is the set of all possible bit loading values defined by the applicable DMT modulation scheme.

Figure 3 shows a DSL transceiver unit RT1 suitable for transmitting DMT modulated signals over twisted pair L1.

For the present invention, the transceiver unit RT1 comprises the following functional blocks:

- Power Control Unit PC,

- transmitter unit TX,

- receiver unit RX,

- hybrid circuit H,

- Line adapter T.

The power control unit PC is coupled to both the transmitter unit TX and the receiver unit RX. Both the transmitter unit TX and the receiver unit RX are coupled to the hybrid H. Hybrid circuit H is coupled to line adapter T.

The transmitter unit TX houses the necessary means for encoding user data and control data and modulating the DSL tones with such encoded data. The transmitter unit houses the necessary means for controlling the transmit power of each tone, which is determined by the power control unit PC.

The receiver unit RX houses the necessary means for demodulating the DSL signal and for decoding user data and control data from such demodulated signal.

The hybrid circuit H is adapted to couple the output of the transmitter unit TX to the twisted pair L1 and to couple the twisted pair L1 to the input of the receiver unit RX. The hybrid circuit H incorporates an echo canceling device to avoid coupling of the signal of the transmitter unit TX into the input of the receiver unit RX.

The line adapter T is adapted to isolate the transceiver unit RT1 from the twisted pair L1 and adjust the input and output impedance of the transceiver unit RT1 to the characteristic impedance of the line.

The power control unit PC is adapted to iteratively determine the operating transmit power of the DSL tones.

The power control unit PC includes the following functional blocks:

- the first agent A1,

- the second agent A2,

- Third agent A3.

The first agent A1 is coupled to the second agent A2, also to the transmitter unit TX and to the receiver unit RX. The second agent A2 is coupled to the third agent A3. The third agent A3 is coupled to the first agent A1.

The first agent uses the interfering channel model described above, where channel _C1 represents line L1. The first agent A1 then assumes that N-1 adjacent channels C2 to C _N interfere with the line L1 _.

Let b _l denote a specific bit load from the set {b ₀ , b ₁ , . . . , b _L }.

Denote a specific pitch with f _k .

Let S _1,k,l denote the transmit power required to carry tone f _k with b ₁ bits on line L1.

From formula (3) we can get:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">S</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">k</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

The peer transmitter unit at the other end of line L1, presently CP1, determines certain channel information from measurements performed on the received signal and noise.

In one embodiment of the invention, the first agent A1 uses the transmit power and the corresponding bit load calculated by the peer transceiver unit for the tone _fk , denoted respectively as SR1 _{, k} and BR _1,k .

The receiver unit RX is adapted to forward these pieces of information, indicated by IR in FIG. 3 , to the first agent A1 .

We get:

$\frac{{\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">k</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="BR"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">BR</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&Gamma;</span>}}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="SR"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">SR</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}$

and

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">S</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="BR"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">BR</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="SR"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">SR</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In another embodiment, the first agent A1 uses noise and direct channel transfer functions measured by peer transceiver units.

In another embodiment, the first agent A1 uses the channel signal-to-noise ratio (C-SNR) measured by the peer transceiver unit $({\mathrm{<figure-callout\; id="1"\; label="CSNR"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">CSNR</figure-callout>}}_{1,k}=\frac{{\left|h_{11,k}\right|}^2}{{\mathrm{\&sigma;}}_{1,\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">k</figure-callout>}}^2+\underset{m\&NotEqual;1}{\mathrm{\&Sigma;}}{S}_{m,k}\&Center\; Dot;{\left|h_{1m,k}\right|}^2}).$

The first agent A1 determines S _1,k,l (S _1,k,0 =0 dB) for all bit loads b ₁ to b _L using formula (5).

Bit loads bl whose corresponding transmit powers S _1,k,l do not comply with some predetermined transmit power constraints are _discarded .

Next, the first agent A1 determines for each S _1,k,l the bit loads available on adjacent channels C ₂ to C _N , denoted B _2,k,l to B _N,k,l respectively.

The first agent A1 uses some level of knowledge about the neighboring systems and transmission environment.

Assume the following data is known in advance:

- N-1 transmit PSDs S ₂ to S _N for transmitters X ₂ to X _N respectively

- N-1 noise PSDs σ ₂ to ^σ _n ² for channels C ₂ to C _N respectively

- N-1 direct transfer function magnitudes |H ₂₂ | to |H _nn | for channels C ₂ to C _N respectively

- N-1 crosstalk transfer function magnitudes |H ₂₁ | to |H _N1 | from transmitter X ₁ to receivers Y ₂ to Y _N respectively.

In one embodiment of the present invention, these data are stored in a non-volatile storage area.

In another embodiment, the transmitter unit RT1 also comprises communication means adapted to retrieve all or part of these data from a remote server.

In one embodiment of the invention, the first agent A1 uses a crosstalk channel model, where the transfer function magnitude | _Hm1 | for tone _fK is given by:

${<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="h\; m"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">h</figure-callout></span><figure-callout\; id="1"\; label="h\; m"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="f\; k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">f</figure-callout></span><figure-callout\; id="2"\; label="f\; k"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

in:

_-Km is the coupling constant between line _L1 and channel _Cm ,

- in terms of l _B the theoretical length of the bundle of the line L ₁ and the channels C ₂ to C _N ,

- the theoretical signal attenuation of the tone f _k on the channel C _m expressed in α _{m k} ,

- Denote in l _m the theoretical length of the channel through which the crosstalk signal from transmitter X ₁ enters receiver Y _m attenuates.

The bit loads B _2,k,l to B N _,k, l that can be obtained on adjacent channels C ₂ to C _N for a given S 1,k _,l can be obtained by the following formula:

Interference between channels C ₂ to C _N is assumed to be included in the noise model σ _m ² .

In another embodiment, the first agent A1 uses another crosstalk channel model understood by those skilled in the art.

The first agent A1 calculates the weighted sum of the bit loads available on line L1 and the bit loads available on channels _C2 to C _N :

${\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="w"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; l</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

The first agent A1 determines the bit loading b _lk that maximizes the weighted sum J _k,1 :

l _k = argmax _l (J _{k, l} ) (9)

The transmit power of tone f _k on line L1 that maximizes the weighted sum J _k,1 is then given by:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">S</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="S"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">S</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; b</span>}}_{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}}^{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="b"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">b</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="SR"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">SR</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

The corresponding bit load on line L1 is given by:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="B"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">B</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{{\mathrm{<span\; class="notranslate">\; l</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

The corresponding bit loading on channels _C2 to C _N is given by:

The first agent A1 re-iterates the process for all tones _f1 to _fK .

The first agent A1 makes B _1,k to B _N,k available to the second agent A2 for all tones f ₁ to f _K , eg by using a shared memory area and one or more software triggers.

The second agent A2 accumulates B _1,k over all tones f ₁ to f _K , thereby determining the total bit load B ₁ :

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="B"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">B</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="K\; B"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">K</figure-callout></span><figure-callout\; id="1"\; label="K\; B"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">\; </figure-callout>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; </span>}}_{}{\mathrm{<span\; class="notranslate">B</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

The second agent A2 accumulates B _2,k to B _N,k over all tones f ₁ to f _K to determine the N-1 total parallel bit loads B ₂ to B _N :

${\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; K</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; k</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

The third agent A3 adjusts the weights w ₁ to w _N such that B ₂ to B _N are respectively greater than or equal to the target rates BT ₂ to B _N , and thus B ₁ is maximized.

In one embodiment of the invention:

${\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="w"\; filenames="A20041005016800231.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}$

If any of the total parallel bit rates _B2 to _BN is lower than its target rate, the corresponding weight is increased by dichotomy. If any of the total parallel bit rates B ₂ to B _N is higher than its target rate, then the corresponding weight is decreased by dichotomy.

In another embodiment, the third agent A3 adjusts the weights w ₁ to w _N using another algorithm known to those skilled in the art.

The new weights are made available to the first agent A1, from which the first agent A1 in turn determines a new transmission power, and so on.

This process continues until a convergence criterion is reached, eg, an interval in which each weight is currently considered to be smaller than a predetermined threshold ε.

The third agent A3 informs the first agent A1 that the process is over. Thereafter, the first agent A1 enables the transmitter unit TX to obtain the final determined S _1,k for all tones f ₁ to f _K .

Transmitter unit TX uses transmit powers S _1,1 to S _1,K in each case for tones f ₁ to f _K .

Those skilled in the art will understand that bit payload or bit rate may be used interchangeably (actually, bit payload is the number of bits transmitted by one tone in the duration of one DMT symbol).

Figure 4 presents the rate regions for different PBO methods, including our proposed scheme. In this numerical analysis, it is assumed that PBO is applied in ADSL deployed by RT interfered by ADSL deployed by CO. Compared with the existing methods, the proposed scheme has achieved significant performance improvement: with 1Mbps as the target data rate on ADSL deployed in CO, ADSL deployed in RT reaches 1.7Mbps in the case of flat PBO, and the reference noise It hit 2.4Mbps with the case, 3.7Mbps with the refill, and 6.7Mbps with the proposed scheme.

Fig. 5 shows another characteristic embodiment of the present invention.

As far as the present invention is concerned, the DSL communication system S comprises the following functional blocks:

- Communication Adapter Module CAM,

- transceiver unit RT2,

- Data communication network DCN.

The communication adaptation module CAM is coupled to the transceiver unit RT2 via the data communication network DCN.

As far as the present invention is concerned, the communication adaptation module CAM includes the following functional blocks:

- the previously described power control unit PC comprising the previously described agents A1 to A3,

- communication means COM1,

- Input/Output Port I/O1.

The first agent A1 is coupled to the second agent A2 and to the communication means COM1. The second agent A2 is coupled to the third agent A3. The third agent A3 is coupled to the first agent A1. The communication device COM1 is coupled to the input/output port I/O1.

The input/output port I/O1 houses the necessary means for encoding and transmitting data on the data communication network DCN and for receiving and decoding data from the data communication network DCN.

The communication means COM1 house the necessary means for communicating with the transceiver unit over the data communication network DCN and for checking the integrity of messages exchanged over the data communication network DCN.

More specifically, the communication means COM1 are adapted to receive from the transceiver unit the channel information IR necessary to calculate the operating transmit power of the transceiver unit and to forward them to the first agent A1.

The communication means COM1 are also adapted to send to the transceiver unit the operating transmit power S _1,1 to S _1,k determined for the transceiver unit by the power control unit PC.

As far as the present invention is concerned, the transceiver unit RT2 comprises the following functional blocks:

- the previously described transmitter unit TX,

- the receiver unit RX described above,

- the previously described hybrid circuit H,

- the previously described line adapter T,

- communication means COM2,

- Input/Output Port I/O2.

Both the transmitter unit TX and the receiver unit RX are coupled to the hybrid H. The hybrid circuit H is coupled to the line adapter T. The communication means COM2 is coupled to the transmitter unit TX, to the receiver unit RX, and to the input/output port I/O2.

The input/output port I/O2 houses the necessary means for encoding and transmitting data over the data communication network and for receiving and decoding data from the data communication network DCN.

The communication means COM2 house the necessary means for communicating with the communication adaptation module via the data communication network DCN and for checking the integrity of messages exchanged on the data communication network DCN.

More specifically, the communication means COM2 are adapted to forward the necessary channel information IR reported by the peer transceiver unit to the communication adaptation module for further processing.

The communication means COM2 are also adapted to receive operating transmit powers S _1,1 to S _1,K from the communication adaptation module and forward them to the transmitter unit TX.

In one embodiment of the invention, the communication adaptation module CAM is housed in the network manager and is coupled to the transceiver unit via a WAN, such as an ATM network.

In another embodiment, the Communication Adaptation Module CAM is mounted on a card and inserted into a card slot of a Digital Subscriber Line Access Multiplexer (DSLAM). The communication adaptation modules CAMs are coupled to the transceiver units of the DSLAMs via a local bus, such as an Ethernet bus, and to remotely deployed transceiver units via their respective links to the DSLAMs.

A final remark is that the embodiments of the invention have been described above in terms of functional blocks. From the functional description of these functional blocks given above, it will be apparent to a person skilled in the art of electronic device design how to manufacture embodiments of these blocks in well known electronic devices. A detailed architecture of the content of these functional blocks is therefore not given.

While the principles of the present invention have been described above in connection with specific devices, it should be clearly understood that this description is illustrative only and not intended to limit the scope of the present invention, which is defined in the appended claims.

Claims (9)

1. one kind is used at least one tone (f ₁To f _K) in each tone determine at least one work transmitting power (S on physical channel (L1) _1,1To S _{1, K}) method, it is characterized in that described method comprises following step:

For each the single tone in described at least one tone is determined transmitting power on described physical channel, thereby described transmitting power makes at available data rate on the described physical channel and on described single tone and at least one model adjacent channel (C ₂To C _N) in each channel on and on described single tone the weighting function maximum of available at least one parallel data speed, it is constrained to, described transmitting power meets transmission power limit,

Therefrom determine on the described physical channel and the total data rate (B that on described at least one tone, can access ₁), and on each channel in described at least one model adjacent channel and at least one total parallel data speed (B that on described at least one tone, can access ₂To B _N),

Adjust each weights (w of described weighting function ₁To w _N), thereby described at least one total parallel data speed is more than or equal at least one target data rate (BT ₂To BT _N) in each target data rate, thereby and maximize described total data rate, it is constrained to, and all is identical at each weights of described at least one the above weighting function of tone,

Determine described at least one work transmitting power by iteration thus.

2. according to the method for claim 1, it is characterized in that: the step of determining described transmitting power is confined in the discrete set by the performed pre-determined data rate of the coding that is adopted on described channel and/or modulation scheme.

3. according to the method for claim 1, it is characterized in that: described weighting function is a weighted sum.

4. a transceiver unit (RT1) comprising:

Transmitter unit (TX) is suitable for going up at least one tone (f of emission at physical channel (L1) ₁To f _K),

Power control unit (PC) is coupled in described transmitter unit, and is suitable for each tone in described at least one tone and determines at least one work transmitting power (S on described physical channel _1,1To S _{1, K}),

It is characterized in that described power control unit comprises:

First agency (A1), be suitable for each single tone in described at least one tone and determine transmitting power on described physical channel, thereby described transmitting power makes at available data rate on the described physical channel and on described single tone and at least one model adjacent channel (C ₂To C _N) in each channel on and on described single tone the weighting function maximum of available at least one parallel data speed, it is constrained to, described transmitting power meets transmission power limit,

Second agency (A2) is coupled in described first agency, and is suitable for therefrom determining on the described physical channel and the total data rate (B that can access on described at least one tone ₁), and on each channel in described at least one model adjacent channel and at least one total parallel data speed (B that on described at least one tone, can access ₂To B _N),

Third generation reason (A3) is coupled in described first agency and described second agency, and is suitable for adjusting each weights (w of described weighting function ₁To w _N), thereby described at least one total parallel data speed is more than or equal at least one target data rate (BT ₂To BT _N) in each target data rate, thereby and maximize described total data rate, it is constrained to, and all is identical at each weights of described at least one the above weighting function of tone,

Determine described at least one work transmitting power by iteration thus.

5. according to the transceiver unit of claim 4, it is characterized in that: described first agency also is suitable for limiting being determined in the discrete set by the performed pre-determined data rate of the coding that is adopted and/or modulation scheme of described transmitting power on described channel.

6. according to the transceiver unit of claim 4, it is characterized in that: described weighting function is a weighted sum.

7. according to the transceiver unit of claim 4, it is characterized in that: described transceiver unit is digital subscriber line (xDSL) transceiver unit.

8. a digital communication system (S) comprising:

At least one transceiver unit (RT2),

Be coupled in the communication adaptation module (CAM) of described at least one transceiver unit by data communication network,

Each transceiver unit in described at least one transceiver unit comprises: be suitable for going up at least one tone (f of emission at physical channel (L1) ₁To f _K) transmitter unit (TX),

Described communication adaptation module comprises: be suitable for each tone in described at least one tone and determine at least one work transmitting power (S on described physical channel _1,1To S _{1, k}) power control unit (PC),

It is characterized in that described power control unit comprises:

First agency (A1), be suitable for each single tone in described at least one tone and determine transmitting power on described physical channel, thereby described transmitting power makes at available data rate on the described physical channel and on described single tone and at least one model adjacent channel (C ₂To C _N) in each channel on and on described single tone the weighting function maximum of available at least one parallel data speed, it is constrained to, described transmitting power meets transmission power limit,

Second agency (A2) is coupled in described first agency, and is suitable for therefrom determining on the described physical channel and the total data rate (B that can access on described at least one tone ₁), and on each channel in described at least one model adjacent channel and at least one total parallel data speed (B that on described at least one tone, can access ₂To B _N),

Third generation reason (A3) is coupled in described first agency and described second agency, and is suitable for adjusting each weights (w of described weighting function ₁To w _N), thereby described at least one total parallel data speed is more than or equal at least one target data rate (BT ₂To BT _N) in each target data rate, thereby and maximize described total data rate, it is constrained to, and all is identical at each weights of described at least one the above weighting function of tone,

Determine described at least one work transmitting power by iteration thus.

9. digital communication system according to Claim 8 is characterized in that: described first agency also is suitable for limiting in the discrete set that is determined to the pre-determined data rate of being carried out by coding that is adopted and/or modulation scheme on described channel of described transmitting power.

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